Display materials, devices and systems



APfl 2l, 1959 P. BOONE DISPLAY MATERIALS, DEVICES AND SYSTEMS FiledSept. 5. 1952 xlHll IN VEN TOR.

United States Patent O DISPLAY MATERIALS, DEVICES AND SYSTEMS PhilipBoone, Winchester, Mass.

Application September 5, 1952, Serial No. 308,096

21 Claims. (Cl. 40-130) This invention relates to improvements indecorative and display materials, devices and methods, and moreparticularly to such improved materials, devices and methods utilizingpolarized light.

The present invention relates to decorative and display materials,devices and systems which provide visible areas of original and strikingappearance through relatively simple constructions and at reasonablecost. They involve the projection, modification and reflection ofpolarized light and are adapted, for example, to window display,interior display, outdoor advertising, decorative and theatrical settinguses. A principal characteristic of the present materials, devices andsystems is their adaptability for combination with presently used orreadily accessible materials and methods in the art to obtain novelresults. This permits improved visual effects relative to existingmaterials and methods but avoids the excessive cost which would beinvolved in completely discarding present techniques.

Accordingly, an object of the invention is to provide light polarizingmaterials, products, devices, methods and systems which provide noveland attractive visual results for decorative, advertising and displaypurposes.

Another object of the invention is to provide improved materials andmethods for achieving the first-named object.

A further object of the invention is to provide the aforesaid materialsand devices in the form of simple and eilicient constructions and atreasonable cost.

A still further object of the invention is to provide novel materials,devices and methods in combination with present materials and methodsused in the art to achieve improved display and decorative products.

Another object of the invention is to provide decorative and displayproducts wherein surface glare is substantially eliminated and effectivereflectivity, contrast and width of viewing angle are obtained.

These and other objects of the invention will be apparent from thefollowing description taken in conjunction with the accompanyingdrawings wherein like reference characters refer to like partsthroughout the several views.

Figure 1 is a front view of an advertising display unit or assembly ofthe invention;

Fig. 2 is a side View, in cross section, illustrating the` method ofattaching composite light-polarizing material of the invention to asection or panel thereof;

Fig. 3 is a similar View of a modification of the method shown in Fig.2;

Fig. 4 is a similar view of a further modification of the methodillustrated in Fig. 2;

Fig. 5 is a similar view of a modified panel or area of the invention;

Fig. 6 is a side view in cross section which illustrates a compositereflecting-light-polarizing material of the invention;

Figs. 7 through l0 are side views in cross section which illustratemodifications of the composite material of Fig. 6.

"ice

Referring to Fig. l, a display area of the invention such as anadvertising panel or pictorial unit is illustrated. This unit is capableof showing visible changes in certain portions when subjected tocontrolled polarized light, and may also show various changes in otherportions when subjected to other types of light. The words always, keepcool," aero and cigarettes and the portions 12, 14, 16, 18, 20 and theborder 22, in a basic construction, are formed of a composite materialcomprising a lightpolarizing element, a nondepolarizing reflectingelement and, preferably, at least a light-diffusing element. Theselight-polarizing-rellecting-diflusing portions will be referred to aspolarizing-reflecting herein. Other sections of the border are to beassumed to have alternate polarizing directions similar to those above.These portions are subject to the above-named changes in polarizedlight. The double-headed arrows indicate polarizing directions or axesof the respective portions. The surrounding area of the unit 24 and theword smoke may be formed of paints, dyes, photographic prints, compositemetallic material, fluorescent or phosphorescent materials et cetera,preferably substantially depolarizing, applied to the panel anddepicting any desired message, scene or design. The compositepolarizing-reflecting material, in certain instances, is attached eitherdirectly to the unit or panel or to sections 26, 28 and 30 which, inturn, are superposed and fastened to the panel. These sections may be ofwood, metal, plastic or any suitable material. Other portions of thepolarizing material, such as the word aero and portions 12, 14, 16, 18and 20 may be bonded directly to the surface 24 of the unit. Border 22may be attached to the unit or to a strip which, in turn, is bonded tothe unit. Any suitable bonding substances or fastening means may beemployed for attaching the composite polarizing-reflecting material orsections. Shading 32 and eye portion 34 represent opaque, translucent ortransparent paint, dye, etc. applied to the surface of the compositepolarizing material. The composite polarizing-reflecting material maysuitably be bonded to the display unit, to section components of theunit as shown in Figs. 2, 3 and 4, or it may of itself form a section orpanel wherein letters and figure areas etc. remain clear and are givenshape by painting around them with opaque paint as shown in Fig. 5. InFig. 2 the composite polarizing-material 36 is attached to a section orunit 38 by a bonding substance 40, the section having a cut-out portion42 through which the polarizing material is visible. In Fig. 3 thecomposite polarizing-reflecting material 44 is inlaid in a cut-outp0rtion 46 of a section or unit 48. In Fig. 4 the compositepolarizing-reflecting material 50 is bonded to the surface of a sectionor unit 51 by a bonding substance 52. In Fig. 5 thepolarizing-reflecting material 53 has an opaque paint 54 applied tocertain surface portions so as to form the contour and surrounding areaof nonpainted functional portions. Operation of the unit of Fig. 1 willfurther be described relative to a coacting polarizing light sourceproviding axially changing polarized light.

Figs. 6 through l0 illustrate various constructions of compositepolarizing and rellecting material which may be used in the unit of Fig.l. In Fig. 6 the construction includes a diffusely-rellecting layer 56and a light-polarizing layer 58, the reflecting layer being somewhatexaggerated. Fig. 7 shows a reflecting means 60, a lightpolarizingelement 62 and a diffusing layer or means 64. Fig. 8 represents areflecting means 66, a light-polarizing means 68 and a diffusinglens-like surface layer 70. In Fig. 9 the assembly includes a reflectingsurface 72, a light-polarizing means 74, a birefringent layer 76 and adiffusing portion 78 which may be a separate layer or incorporated withthe preceding layer. Fig. l0 illustrates a reflecting layer 8|), abirefringent layer 82, a polarizing layer 84 and and a diffusing means86. In the foregoing constructions, the respective layers are preferablylaminated or bonded together by any suitable means, using subcoats asnecessary, or the reflecting and diffusing layer may be coatings appliedto the polarizer. In turn, the polarizer could be a coating applied toeither the reflecting or diffusing layer. Bonding materials, such aspolyvinyl alcohol, vinyl resins, polyvinyl butyral, cellulose acetate etcetera, may be used, depending upon the layer materials employed. Thereflecting layer may be located in its functional area and held inassembled relation by any other suitable fastening means in amodification. Or. the reflecting layer could be formed on the supportingunit and any of the constructions of Figs. 5, 6, 7, 8, 9, l0, minus areflecting element, be bonded thereto.

The light-polarizing elements of the constructions of Figs. 1, 6 throughl0, and of polarizing light source means, used therewith, may be formedof any suitable commercially available polarizing material. Suchmaterial is manufactured as a film by Polaroid Corporation, Cambridge,Massachusetts, and as a coating by Polacoat Corporation, Blue Ash(Greater Cincinnati), Ohio. The reflecting coating may, for example,consist of aluminum foil (preferably employing a matte surface thereof),a deposition in vacuum of aluminum, a metallic coating applied, forexample, by a spray, brush or dip method, or a chemical deposition.Alternatively, the reflecting layer could be applied as a metallicpowder (i.e., aluminum) to a surface of the polarizer which has beensoftened by a solvent or which has been treated with a transparentadhesive. If, for example, the polarizer has an acetate supporting layerit could be treated briefly with acetone and the aluminum powder appliedthereto. The diffusing layer may, for example, be a "flat varnish orlacquer, a plastic layer applied by a dipping, laminating or sprayingprocess, a sand blasted, rubbed or otherwise produced matte surface. Thebirefringent layer may be formed of stretched polyvinyl alcohol,cellulose acetate, ethyl acetate, regenerated cellulose or any suitablematerial. The rear surface of the reflecting means, as well as edges andfrontal surface of the composite material, may be protected againstweathering by a suitable varnish, lacquer or other transparent coating.Any of the components of the composite materials of Figs. 6 through l0may embody a tint, a dye, a fluorescent or phosphorescent substance orthe like so as to provide a color or a luminous characteristicespecially when the display unit is subjected to a source such asdaylight, nonpolarized artificial light, ultraviolet light, et cetera.

In the constructions of Figs. 6, 7 and 8, incident axially varyingpolarized light is blocked by the polarizing layer when vibrating at 90to the vibration direction of the layer, thus producing extinction or adark appearance of the composite material. If the polarizing lightsource includes a birefringent element in the path of axially varyingpolarized light, an interference phenomenon produces color changes inconstructions of Figs. 6, 7 and 8. Further interference color changesare possible through the construction of Fig. 9. The assembly of Fig. l0shows interference colors in normal light and further changes ofinterference color and reflectivity in changing polarized light.

Again referring to Fig. 1, assuming that its composite polarizingportions are generally similar to constructions of Figs. 6, 7 or 8 andthat section 28 surrounding the words keep coo is of a dark quality,than axially changing polarized light from a projector will produce thefollowing effects. The words always and cigarette and portions 16, 18and 22a will change from bright to dark, or vice versa. The words keepcool and portions 14 and 22h will equally change during a second 90rotational cycle. The word aero and portions 12, 20 and 22e will undergoan equal change during a third 90 rotational cycle. The second and thirdcycles commence within the first cycle. At its dark stage, keep coolwill merge into the dark surrounding area of section 28 and disappear."At its dark stage, eye 14 will apparently close. The smoke 18, 20 andborder 22 will apparently be iii continuous movement. The word smoke isformed of a conventional paint, dye, fluorescent substance or the like.Because the polarizing light source constantA ly illuminates the entireunit, areas other than those above described constantly reflect incidentlight rays. Shaded areas of the word aero, the figure of the girl. thecigarette and the background may be formed of other materials such asdescribed relative to the word "smoke. lf embodying fluorescentsubstances, for example, they may show special effects when subjected toultraviolet light alternatively produced, for example, by anulti'aviolet light source and timer. Also, certain portions of the unitmay be outlined by neon tubes or comprise incandescent bulbs foralternate effects controlled by a timer. The unit of Fig. l is merelyillustrative and ii will be apparent that through controlled orientationof polarizing-reflecting portions, which may also include a horizontaland other directions of orientation, use of dyes and pigments therewithet cetera, many other effects mayv be obtained involving change andanimation. As ex amples these could include effects of changing baci;-grounds, moving fluids, clouds, snow, objects, word messages and thelike. Furthermore, certain arcas of theunit may be treated independentlyof other areas by limit ing areas which are illuminated by individuallight sources. One light source may be a polarizing source, such asdescribed herein, while the second source provides unpolarized light.Or, for example, both sources may be polarizing, though providingsimultaneously dit ferent directions of polarization. i

Assuming the use of a birefringent element with the source of varyingpolarized light, color changes will be visible in the unit of Fig. l.These changes will occur in the various portions as cycles substantiallyin the order described relative to changes from dark to bright, andsimilar colors will be visible in portions similarly oriented. Thecolors are determined by the birefringence of the doubly refractngelement employed, namely, by the thickness, relative direction of aprincipal axis and degree of orientation of the element. A 90 rotationof the polarizing element of the light source will, for example, providecomplementary colors in any given polarizingreflecting portion of theunit of Fig. l. Additional color effects are obtained if thepolarizing-reflecting material contains a light-absorbing dye, tint orthe like, as above described.

In a lightpolarizing display system such as exemplified by the presentinvention, it is of the utmost importance to prevent visible surfacereflection of the light source and to substantially eliminate visiblesurface reflection of extraneous light by the light-polarizingreflectingmaterial employed. It will be apparent that such surface reflectionswould prevent the material from appearing dark when the polarizing axesof the projector and material components are crossed at 90. Coloreffects produced by a birefringent projector element would also beseriously impaired. The type of reflection required is that wherein theincident rays pass through polarizing means. and, according to theconstruction, through diffusing and retarding means, to the reflectingmeans and return. The aforesaid undesirable surface reflections aresubstantially reduced by providing reflection-reducing, diffusing ormatte surface means, examples of which are shown in Figs. 7 through 10.Any remaining surface reflections may be rendered substantiallyimperceptible by controlling the location and projection characteristicsof polarizing light source means with respect to a display unit so thatsurface reflection of rays by the unit is caused to be invisible to theviewer. As an example, using a Projector Flood" lamp manufactured byGeneral Electric Company, Schenectady, N.Y., in a polarizing projectorhaving an optical axis tilted at 45 relative to the plane of a displayunit and spaced at ve feet from the unit, no surface glare frompolarizing-reflecting portions distributed throughout the unit werevisible at distances exceeding live feet from the unit. It will beapparent that correct angles of rays may be determined for all viewingpositions relative to polarizing display systems located at variousheights, horizontal positions and distances and that projectors may bepredeterminedly positioned for providing these angles. It will befurther apparent that a slight tilting of the display unit may beemployed for contributing to correct angles of the rays relativethereto.

A second important consideration in an efficient polarizing-reflectingdisplay system is the reflection of polarized rays from the unitthroughout a sufliciently wide angle for general viewing purposes. Thismay be achieved by providing within a polarizing-reflecting portionsuitable reflecting and diffusing properties of its reflecting means,predetermined diffusing properties of its surface layer or element,diffusing and collimating means associated with the light source and bya predetermined projection angle (optical axis) of the polarizing lightsource (projector). Each of these constructions or controls may beutilized or they may be employed in the system as a carefully balancedcombination of cooperating means. For example, a polarizing-reflectingmaterial providing an extremely wide angle of reflected rays includes areflecting means formed by spraying an aluminum paint, powder or lacqueron a surface of polarizing material comprising a film of treatedpolyvinyl alcohol bonded to cellulose acetate or cellulose acetatebutyrate. A polarizing film backed by the matte surface of aluminum foilprovides possibly a more brilliant reflectivity but a narrower angle ofreflected rays. A chemical or vacuum deposition of metal (i.e.,aluminum) on a preferably matte-formed surface of the polarizer,constitutes another suitable reflecting means.

A third important consideration in display devices and systems of theinvention is the reflection of adequate light from polarizing-reflectingareas relative to the type of display unit and viewing distancescontemplated. Thus, a unit providing changes in wording which areintended to be visible at a considerable distance may require greaterbrilliance in the polarizing-reflecting portions than is required offigure or design changes in window display or other interior use. Formaximum brilliance throughout a relatively narrow angle, aluminum foil,deposition coatings and the like may, for example, be employed as areflecting means, as above described. The intensity of the light sourcemay also be increased. Because commercial types of polarizers oftentransmit preferentially within certain wavelength bands, light sourceswhich provide illumination preferentially or substantially completelywithin those bands may advantageously be used. Thus, for example, wherethe polarizer transmits more favorably a yellow-green wavelength, asodium type of light source may present advantages in producingreflected rays from the polarizing-reflecting areas of increasedvisibility. In other instances, a mercury vapor type of lamp may beemployed. In general, however, conventional incandescent light means aresatisfactory. It will be understood that the limitations of therelatively narrow angle, above-referred to, may be overcome by using aplurality of light source means, in which case functional reflected raysare visible from all required viewing angles. Thus, for example, aplurality of projectors may project a plurality of cones of light ofgiven angular width and, through the reflecting, polarizing anddiffusing properties of the constructions exemplified in Figs. 6 through10, coacting therewith, a plurality of cones of reflected rays of lightof narrower angular width may be produced. These reflected rays may beof marked brilliance and, through the aforesaid angular positioning ofthe projectors, bundles of the rays are visible from any requiredviewing position. Where, as above-described, less brilliance isrequired, the reflecting-polarizing material may have a reflectingelement which provides adequate but less brilliant reflectivitythroughout a wide angle. Such an element is provided by the metallicpaints, powders, sprays or lacquers, above referred to, applied to thepolarizer. A very satisfactory reecting means of this type is providedby Krylon Aluminum Acrylic Spray manufactured by Krylon, Inc.,Philadelphia, Pa. It is to be understood that the diffusing layer ortreatment shown in Figs. 7 through 10 and above described relative toelimination of surface reflections also widens the angle of visible raysfrom the polarizing-reflecting material and may be employed to advantagewith the various types of reflecting means of the invention. Thediffusing layer also modifies the polarization of polarized rays fromthe projector and thus modifies the contrast and quality of colorsprovided in the polarizing-reflecting areas. Thus the degree ofdiffusion provided depends upon the exigencies of reduction of Surfaceglare, increase in visual angle and modification of polarization ofincident rays required in a given system to produce a given result. Tobe balanced with the aforesaid diffusing means of various degree are thevarious reflecting means, types of light sources and relativepositioning of light means and display units previously described.

From a commercial aspect, it is to be understood that materialsdescribed herein and exemplified in Figs. 5 through l0, may be suppliedwith or without reflecting elements, that adhesive means may be formedon the back or specially supplied therewith, that opaque or translucentdesigns or configurations may be formed on the front surface and thatpolarizing elements may have a plurallty of orientations. The latter maybe achieved by a single layer having several orientations or a pluralityof sections carried by a support. Where birefringent elements areemployed they may similarly have several retardation values. Thematerials may be marketed in panel or roll form or in special shapes.

Polarizing elements of the display unit may be composed, entirely, orpartially in conjunction with the plane polarizing elements hereinbeforedescribed, of circularly polarizing materials, i.e., of right-handed andleft-handed polarizing film materials, in which instance they would beused with light sources having variable rightand left-handedlight-polarizing filters. The use of circular polarizers assupplementary means would provide changes, such as those of animationand color, additional to the changes visible in the plane polarizingareas of the display.

Where half-tone effects are desired, translucent paints or dyes may beapplied to areas of the polarizing-reflecting material. It will also beapparent that a transparent photosensitive layer may be applied to saidmaterial and photographic prints produced thereon. If desired, one ormore of the functional portions of Fig. 1 may be cut out of thesupporting unit 24 and have any of the constructions of Figs. 7 throughl0, without the reflecting element thereof, placed over the cut outportions. For projecting polarized rays on said portions, a projector ofthe type described herein could be positioned at the rear of the unit toprovide, through a transmission system, changes somewhat similar tothose of the reflection systems of the invention. Polarizing orretardation material used in the display unit may be of a type having acontinuously varying orientation rather than the fixed orientationsshown, for providing modified effects. It will further be apparent thatany of the constructions of Figs. 7 through 10 could be made without thereflecting layer and could be applied to suitable reflecting areas ofthe display unit or panel by an adhesive associated with saidconstructions or separately applied.

For further modification of color eects, where bircfringement andpolarizing elements are included in a projector, both elements may bemounted for movement.

Or, a plurality of optically aligned birefringent elements may be used,one or more of which are axially movable. The use of colors or tones inareas of the unit surrounding the polarizing-reflecting portions whichare of lighter shade or hue than the extinction (dark) appearance ofsaid portions provides an effect of motion, Le., swinging movement, inthe portions during the change cycle thereof, above described. Shadingapplied to marginal areas of polarizing-reflecting lettering or figures,as in the word aero of Fig. l, also contributes to a visual sense ofmotion of said lettering or figures during the change cycle. This effectis enhanced by positioning differently oriented polarizing-reflectingareas adjacent one another. The use of complementary colors inpolarizing-reflecting and surrounding portions may be used for contrasteffects as well as other colors and contrasts in quality or intensity ofcolor and the like.

Polarizers having various transmission properties may be employed in thepolarizing-reflecting elements of a display unit or projector, or both.Where a maximum "dark" is desired at extinction relation of the axes, apolarizer providing a lower percent of transmitted light may be used.Where maximum brightness of reflected light is required at transmissionrelation of the axes, a polarizer providing a higher percent may beemployed. Treatment of surrounding areas may well determine the type ofpolarizer to be used. ln general, polarizers transmitting 38% or greaterof incident light have been found satisfactory. The aforementionedtendency of certain polarizers to transmit preferentially in certainwavelength K bands may, in addition to influencing choice of a lightsource, be employed of itself to provide color in polarizing-reflectingareas of a display unit or to reinforce or modify interference colorsproduced by the use of birefringent components in the system. Where atint, dye or the like is used in the polarizing-reflecting assembly, asfor example, in a surface layer to provide color by daylight, as abovedescribed, deep colors should be avoided in favor of pastel shades ortoo great absorption of incident polarized rays will occur duringoperation therewith of the polarizing projector. Furthermore, the colorsutilized should preferably be within the preferential wavelengthtransmittal band of the polarizer, the preferential wavelength band ofthe light source means and, where a birefringent element is used, shouldreinforce interference colors produced thereby. Soft green,yellow-green, yellow or rose tints have been found to be satisfactoryfor this purpose. Any of the other components of the assembly maycomprise such a tint or dye, if desired, as for example, to reinforceother color-providing means above described. Where lettering, figures,etc. of the display unit of Fig. l are shown as polarizing-reflectingportions, it will be understood that background areas may be ofpolarizing-reflecting construction and that said lettering and figuresmay be as described or formed of nonpolarizing materials.

In display units of the type described herein, marked contrast betweenpolarizing-reflecting and adjacent areas is of extreme importance forheightened visibility of the polarizing-reflecting areas. Accordingly,colors or neutral tones employed in areas surrounding thepolarizingreflecting portions are advantageously of low reflections orhigh absorption and "flat or matte surfaces are suitably provided insaid surrounding areas. Treatment of these areas may be predeterminedwith respect to characteristics, i.e., predominant wavelengths, of thelight source so that maximum reflectivity of the polarizingreflectingportions is accompanied by low reflectivity of the surrounding areas.Large surrounding White areas may well be avoided.

Where a sheet or film type of light polarizer has been referred toherein which comprises a transparent plastic support as, for example, asheet of cellulose acetate or cellulose acetate butyrate to which a thinlight-polarizing film such as oriented polyvinyl alcohol is bonded, amodification of this construction could be employed at reduced cost in amaterial of the present invention. This modification contemplateselimination of the abovementioned initially supporting plastic sheet andbonding of the polarizing film to a metallic surfaced paper or the ilteof any desired rigidity or flexibility. An inherently unsupported filmis defined herein as one which, prior to a described construction, hasnot been laminated to a supporting material. Assuming such a paperhaving a metallic reflecting and preferably diffusing surface to beused, and tnyt a thin film of oriented polyvinyl alcohol is to be usedin forming the light polarizer, a subcoat comprising polyvinyl alcoholis formed on the metallic surface. 'The inherently unsupportedpolarizing film is then laminated to the surface, using a polyvinylalcohol dope or water as the laminating agent. The polyvinyl alcoholfilm may subsequently be treated with a polarizing dye or the lil-ze, ormay be treated to become light polarizing prior to lamination by variousmethods known to the art. The exposed surface of the polarizing film maythen be treated with any of the protective, diffusing or color providingcoatings disclosed herein. Alternatively, the metallic reflecting layermay first be formed on the oriented film of polyvinyl alcohol as, forexample, by any suitable method of forming a reflecting layer describedherein, and the surface so formed may be bonded to the supporting paper.Another method would involve forming a rear surface-reflecting coatingon a transparent base material and bonding the polarizing film to asubcoat formed on the front surface of said base material. If a paper isused as the supporting or backing material, it may advantageously becoated or impregnated with a substance to repel moisture and thusacquire hydrophobic characteristics. Where a birefringent layer isincluded in the construction, as for example an oriented film ofpolyvinyl alcohol, this layer could first be bonded to the metallicsurface, as described relative to the polarizing film. The polarizingfilm could then be bonded directly to the birefringent layer using apolyvinyl alcohol dope or Water as the bonding agent. If other types oflight polarizers requiring a supporting element are employed, it will beapparent that an opaque material, such as a paper, may similarly be usedfor the purpose. Thus, for example, if a light polarizer formed as acoating applied to a prepared surface and previously referred to hereinis employed, such a coating could be applied to the metallic reflectingsurface of the paper. Although the polarizing elements shown in Figs. 5through l0 are represented as of substantial thickness, it is to beunderstood that they may either incorporate a transparent supportinglayer or be relatively much thinner than shown and rely upon a backingmaterial for the reflecting layer as a support. It is also to beunderstood that where the polarizer incorporates a transparentsupporting layer, the reflecting layer may be in the form of arelatively thin reflecting coating applied thereto, as described herein.Thus, the actual and relative thicknesses of the layers in Figs. lthrough 5 are generally exaggerated and are only to be construed in anillustrative sense to indicate the type and relative location ofcomponents.

It is to be understood that the display area or assembly referred toherein does not necessarily have a planar working surface and that saidsurface may be curved or comprise portions which are curved or otherwiseformed to provide a three-dimensional effect and that depolarizing andnondepolarizing portions may be included. Thus the display assembly mayhave a plurality of working surfaces, such surfaces being considered asthose comprising an area or portion constructed and responsive topolarized light of the type described herein.

A light source employing a variably polarizing element which is rotatedby other than electro-mechanical means may be employed where a lessexpensive projector is desired. As an example, a cylinder formed oflightpolarizing sections having different directions of polarizaaesaeaition is suspended from a support having vanes formed therein. Thesupport is rotatably mounted over a light source having a refiector sothat light rays are directed through alternate polarizing sectionsduring rotation of the cylinder, rotation occurring through action ofheat from the light source relative to said varies in a manner known tothe art. Alternatively, the rotating polarizer could be a frusto conicalelement formed from a suitably shaped area of polarizing sheet material.Such a polarizer would provide a continuous change of direction ofpolarization of the light rays during its rotation. It will be apparentthat birefringent elements could also be similarly formed and rotated byheat actuated means for providing varying retardation of components ofthe light rays.

A rear reecting surface having particularly desirable properties ofreflectivity and diffusion is that in which small dry metallic particlesare applied to a prepared rear surface of a transparent material. Thismethod is exemplified in constructions of Figs. through 10 wherein thereflecting layer is described as formed on a polarizing or birefringentelement. A method of forming such a reflecting surface as a continuousprocess is as follows. A supply of transparent sheet material, such as alightpolarizing film, is mounted on a feed roller and is metered througha suitably compartmented chamber. A thin coating of a transparentadhesive or bonding substance, such as a lacquer, is continuouslyapplied to the sheet material. The coating is brought to a tackycondition, as by heat and/or air circulation means. Fine, dry metallicparticles, such as powdered aluminum, are evenly applied to the tackysurface. These particles may suitably be blown upon the tacky surface bycompressed ar means from one or more appropriately directed apertures toprovide a fine dispersion or dusting on" of the particles.Alternatively, the chamber may be continuously filled with circulatingparticles or they may be applied by falling upon the surface fromcontrolled feed means. During application of the metallic particles, theedges of the moving sheet material may advantageously slide upon orbetween strips of felt or the like so that a seal is formed to preventthe metallic particles from entering the area of the compartment facingthe opposite side of the sheet material. After the metallic particlesare applied, the tacky surface is at least partially hardened by heatand/or air circulation means and a protective coating is then applied tothe exposed area of the metallic coating by any suitable method, such asby spraying a lacquer thereon. After suiciently hardening the bondingand protective materials, the coated sheet material may be wound on atakeup roll, preferably using a nonadhering paper between successivelayers of the roll. Alternatively to employing an adhesive or bondingsubstance, where the construction of the sheet material permits, asurface thereof may be softened, as by a solvent or by heat, and broughtto a suitable tacky condition for applicaton of the metallic particles.The above procedure is not necessarily limited to a continuous processor to the material described but may be applied in separate steps and tovarious light transmitting materials and products where such areflecting coating is of advantage.

Various other modifications of the devices and systems described hereinwill be apparent. Accordingly, such examples as have been presented areto be regarded as illustrative and the invention may be otherwiseembodied and practiced within the scope of the following claims.

I claim:

l. A composite sheet material comprising a light polarizing layer, and alight transmitting and diffusing layer, said layers being held togetherin bonded relation and said diffusing layer having an exposed surfacearea providng a given diffusion of incident light rays.

2. A composite sheet material according to claim l in which the lighttransmitting and diffusing layer comprises a color-providing substance.

3. A composite sheet material comprising in order of arrangement a lightrefiecting layer, a light polarizing layer, and a light transmitting anddiffusing layer, said layers being held together in bonded relation.

4. A composite sheet material comprising a light polarizing layer, abirefringent layer, and a light transmitting and diffusing layer, saidlayers being held together in bonded relation.

5. A composite sheet material comprising a supporting layer, a lightreflecting layer formed on said supporting layer, a light polarizingfilm bonded to said light reiiecting layer, and a light transmitting anddiffusing layer formed on the exposed unbonded surface of said lightpolarizing film.

6. A composite light refiecting sheet material comprising a sheet-likebase material, a reflecting layer formed on a surface of said basematerial, a subcoat bonding layer formed on said refiecting layer, and alight transmitting inherently unsupported oriented film bonded to saidsubcoat bonding layer.

7. A composite sheet material according to claim 6 in which a lighttransmitting and diffusing layer is formed on the exposed surface of theoriented film.

8. A composite light reecting and polarizing sheet material comprising asheet-like base material, a reliecting layer formed on a surface of saidbase material, a subcoat bonding layer formed on said reflecting layer,and an inherently unsupported light polarizing film bonded to saidsubcoat bonding layer.

9. A composite sheet material comprising a sheet-like base material, arefiecting layer formed on a surface of said base material, a subcoatbonding layer formed on a surface of said base material, a birefringentlayer, lightdiffusing means and an inherently unsupported lightpolarizing film, one of said brefringent layer and light polarizing filmbeing bonded to said subcoat bonding layer and said birefringent layerand light polarizing film being bonded together.

10. A display device for use with a source of substantially whitepolarized light and means for varying the direction of the polarizingaxis of said polarized light, said display device comprising avertically extending support means, a display area mounted on saidsupport means, isotropic image means forming a first part of the subjectmaterial carried by said display area, and a plurality of laterallydisposed and at least in part contiguous isotropic and light-polarizingimage means forming a second part of said subject material, said firstpart of the subject material appearing stationary when subjected toaxially varying polarized light and said second part of the subjectmaterial appearing to undergo movement when subjected to said axiallyvarying polarized light.

1l. A display device as defined in claim l0 wherein said isotropic imagemeans constitutes a major portion of said subject material.

l2. A display device as defined in claim 10 wherein said isotropic imagemeans is substantially opaque and said light-polarizing image means issubstantially transparent.

13. A display device as defined in claim l0 wherein said isotropic imagemeans is formed of nondichroic lightabsorbing densities and saidlight-polarizing image means is formed of dichroic differentiallylight-absorbing densities.

14. A display device as defined in claim 10 wherein said image means aresubstantially nonbirefringent.

l5. A display device as defined in claim l0 wherein said support meansis formed of an opaque sheet material.

16. A display device for use with a source of substantially whitepolarized light and means for varying the polarizing axis of saidpolarized light, said display device comprising vertically extendingsupport means, a display area mounted on said support means, isotropicimage means forming a first part of the subject material carried by saiddisplay area, a plurality of laterally disposed and substantiallycontiguous isotropic and transparent light-polarizing image meansforming a second and complementary part of said subject material, andrellecting means optically aligned with at least said light polarizingimage means, said rst part of the subject material appearing stationarywhen subjected to axially varying polarized light and said second partof the subject material appearing to undergo movement when subjected tosaid axially varying polarized light.

17. A display device as defined in claim 16 wherein a frontal surfacefacing said light source comprises lightdiffusing means.

18. A display device for use with a source of substantially whitepolarized light and means for varying the polarizing characteristics ofsaid polarized light, said display device being adapted to functionallyreect light which is incident thereupon and comprising a generallyvertically arranged support means, means providing a display areaadapted to carry pictorial subject material mounted on said supportmeans, nondichroic image-forming means providing a first part of thesubject material carried by said display area, a plurality of laterallycontiguous dichroic and nondichroic image-forming means providing asecond and complementary part of said subject material, metallicdiffusely light-reflecting means positioned behind at least saiddichroic image-forming means, and lightdiffusing means incorporated witha surface of said display device, said first part of the subjectmaterial appearing stationary when subjected to axially varyingpolarized light and said second part of the subject material appearingto undergo movement when subjected to said axially varying polarizedlight.

19. A display device as defined in claim 18 wherein is included a sourceof polarized light focused to direct polarized light rays upon a frontalsurface of said device at an acute angle.

20. A display device as defined in claim 19 wherein a substantiallyuniformly birefringent element is optically aligned with one of saidsource of polarized light and said dichroic image-forming means.

2l. A display device for use with a source of substantially Whitepolarized light and means for varying the direction of the polarizingaxis-of said polarized light, said display device comprising meansproviding a substantially planar display area, nondichroicdensity-providing means forming a major part of the subject material ofsaid display area, a plurality of complementary laterally contiguousdichroic and nondichroic density-providing means forming a first minorpart of said subject material, and a plurality of laterally contiguousdichroic density-providing means having relatively differing polarizingaxes forming a second minor part of said subject material, saidnondichroic major part of the subject material appearing stationary whensubjected4 to axially changing polarized light and said first dichroicand said second dichroic and nondichroic minor parts being complementaryto said major part and appearing to undergo movement when subjected tosaid axially changing polarized light.

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